XXII LIST OF WOOD-CUT ILLUSTRATIONS 



PAGE 



43. Diagram of Reversing Prism of ditto 86 



44. Nachet's Double -bodied Microscope 87 



45. Arrangement of Prism, &c, in Powell and Lealand's Binocular 



for high powers 88 



46. Draw-tube with Erector 90 



47. Diagram of Nachet's Erecting Prism 91 



48. Nachet's Erecting Eye-piece 91 



49. Sorby-Browning Spectroscope Eye-piece 92 



50. Arrangement of Prisms in ditto 93 



51. Jackson's Eye-piece Micrometer 96 



52. Hartnack's Eye-piece Micrometer 97 



53. Microscope arranged for Drawing 99 



54. Diagram of Chevalier's Camera Lucida 101 



55. Diagram of Nachet's Camera Lucida 102 



56. Brooke's Nose-piece, modified by Powell and Lealand. . . 103 



57. Collins's Graduating Diaphragm 107 



58. Ross's Achromatic Condenser 108 



59. Smith and Beck's ditto 109 



60. Powell and Lealand's ditto 109 



61. Webster Condenser, fitted with Collins's Graduating Diaphragm 111 



62. Amici's Prism 113 



63. Parabolic Illuminator 115 



64. Diagram of action of ditto 116 



65. White-cloud Illuminator 117 



66. Fitting of Polarizing Prism 118 



67. Fitting of Analyzing Prism 119 



68. Selenite Object-Carrier 120 



69. Condensing Lens 121 



70. Bull's-eye Condenser 122 



71. Beck's Parabolic Speculum 123 



72. Crouch's Adapter for ditto 123 



73. Diagram of Lieberkiihn 125 



74. Beck's Vertical Illuminator 126 



75. Stage-Forceps 127 



76. Beck's Disk -holder 123 



77. Morris's Object-holder 129 



78. Aquatic Box 130 



79. Zoophyte-Trough 132 



80. Compressorium 133 



81. Ross's Compressorium 134 



82. Dipping Tubes 135 



83. Glass Syringe 136 



84. Forceps 137 



85. Bockett-Lamp 141 



86. Section of Adjusting Objective 150 



87. Arrangement of Microscope for Transparent Objects . . . 154 



88. Effect of different modes of Illumination on Pleurosigma for- 



mosum, after Beck 159 



89. Arrangement of Microscope for Opaque Objects .... 161 



90. Hexagonal Areolation of Pleurosigma angulatum, after Wenham 167 



91. Valve of Surirella gemma, after Hartnack 182 



92. Spring-Scissors 187 



93. Curved Scissors 188 



94. Valentin's Knife . 189 



